A novel approach for the computation of orthonormal polynomial expansions

In this paper we present a novel technique for the computation of orthonormal polynomial expansions. The proposed method is very straightforward; given a function to be expanded in a polynomial series, we first use the FFT to compute a vector of Fourier coefficients. Then, using a change of basis transformation, we go from the Fourier coefficients to the polynomial coefficients. Convergence properties for this new approach are investigated.     

Aflavinine,a novel indole-mevalonate metabolite from tremorgen-producing aspergillusflavus species

The structure of aflavanine, a new diterpene indole from $\text{A}$. $\text{flavus}$, is presented.     

(μ-dithio)bis(tricarbonyliron) as an organic disulfide mimic: insertion of low-valent metal species into the sulfursulfur bond

Low valent metal species: (Ph₂PCH₂CH₂PPh₂)Ni⁰, (Ph₃P)₂Pd⁰, (Ph₃P)₂Pt⁰, η⁵-C₅H₅ Co^I and (CH₃)₂Sn^II insert into the SS bond of (μ-S₂)Fe₂(CO)₆ under mild conditions. Identical products were obtained by reactions of the dianion, [(μ-S₂)Fe₂(CO)₆]^2? with the corresponding metal chlorides.     

Na 32P-32D line broadening by Ne,Ar, and Xe

The normalized emission intensity in the wings of the optically thin Na 3²P-3²D lines broadened by Ne, Ar, and Xe has been measured in emission from a high-pressure discharge. A blended satellite occurs about 80 cm^-1 into the Na-Xe red wing and a progression of increasing red wing intensity from Ne to Ar to Xe is observed. Xe densities of 2.5 and 9.1 × 10¹⁹ cm^-3 were used, and the pressure dependence of the NaXe line shape indicates that multiple perturber interactions are important in the far wing at the higher noble gas densities.     

The mass spectra of 5,10-dihydro-5-10-o-benzenophenarsazine (azarsatriptycene) and its oxide

The fragmentation of azarsatriptycene and its oxide proceed with initial rearrangement of the molecular ion to give polycyclic systems: it is suggested that similar rearrangements may account for the behaviour of triptycene itself in the mass spectrometer.     

Structure of 72,74Se at high spin

Lifetimes of high spin states up to { }=22⁺ in the yrast positive parity bands have been measured to investigate the shape evolution with increasing spin in ^{72, 74}Se. The Q _t values derived from these measurements indicate that prolate shape stabilizes for ⁷²Se, while a triaxial shape develops for ⁷⁴Se at higher spins. Comparison of the observed trend in Q _t with spin for ^{72, 74}Se with that of the corresponding kryptones isotones emphasizes the stability provided by N=38 prolate shell gap even at high rotational frequency.     

Stabilization of large generalized Lotka-Volterra foodwebs by evolutionary feedback

Conventional ecological models show that complexity destabilizes foodwebs, suggesting that foodwebs should have neither large numbers of species nor a large number of interactions. However, in nature the opposite appears to be the case. Here we show that if the interactions between species are allowed to evolve within a generalized Lotka-Volterra model such stabilizing feedbacks and weak interactions emerge automatically. Moreover, we show that trophic levels also emerge spontaneously from the evolutionary approach, and the efficiency of the unperturbed ecosystem increases with time. The key to stability in large foodwebs appears to arise not from complexity per se but from evolution at the level of the ecosystem which favors stabilizing (negative) feedbacks.